Eye injections (intravitreal injections)

An intravitreal injection is a medical procedure where medication is delivered directly into the vitreous cavity, the clear gel that fills most of the eye's interior. This method allows the drug to reach the retina and surrounding tissues at a high, effective concentration, while minimizing systemic exposure to the rest of the body. These injections are a primary treatment for a wide range of eye diseases affecting vision.

Intravitreal injections are used to treat numerous conditions, including wet age related macular degeneration (AMD), diabetic macular edema (DME), and macular edema resulting from retinal vein occlusions. They are also effective in certain cases of intraocular inflammation or abnormal blood vessel growth. The specific type of medication is chosen based on the diagnosed disease and its characteristics.

The main medications used in intravitreal injections are anti VEGF (Anti Vascular Endothelial Growth Factor) drugs. VEGF promotes abnormal blood vessel growth and fluid leakage, and these medications block its action. Examples include Bevacizumab, Ranibizumab, and Aflibercept. In some cases, particularly for diabetic macular edema or retinal vein occlusions, steroids injected into the eye, such as a sustained release dexamethasone implant, may be used. Each medication has its own profile of action and potential side effects.

The injection is performed under sterile conditions, typically in a dedicated treatment room. First, the eye is anesthetized using topical anesthetic drops. Then, the area around the eye and eyelids is thoroughly disinfected with an antiseptic solution to minimize the risk of infection. A small eyelid speculum is placed to keep the eye open. The medication is injected with a very fine needle through the white part of the eye, usually with minimal discomfort. The entire procedure is brief, lasting only a few minutes.

Before the injection, it is crucial to provide the medical team with complete information about any underlying medical conditions, regular medications, allergies, and previous reactions to treatments. You must also inform your doctor if you have any active eye infection, such as a stye or pink eye, as the injection may need to be postponed to prevent severe internal infections. The risks associated with intravitreal injections are rare but do exist. The most severe complication is intraocular infection, which can lead to severe vision loss. Other risks include minor conjunctival bleeding, increased intraocular pressure (particularly with steroid medicines), retinal tear or detachment, and lens injury. The medical team will explain the specific risks relevant to your medication and condition.

After the injection, you may experience mild discomfort, stinging, or a foreign body sensation in the eye, as well as a small superficial bleed on the conjunctiva that usually resolves within a few days. Sometimes, small black spots, which are tiny air bubbles, may be seen in the field of vision and typically disappear on their own. It is important to avoid rubbing the eye and maintain good hygiene. Intravitreal injections are often part of a series, and the frequency of injections is determined by the treating physician based on the eye's response and follow up examinations. Even after vision improvement, regular follow up is essential.

You should seek immediate medical attention if you experience any of the following symptoms after the injection: increasing and significant eye pain, marked and persistent redness, sudden or significant decrease in vision, extreme light sensitivity, or the sudden appearance of many new 'floaters' accompanied by flashes of light. These symptoms could indicate a complication requiring urgent treatment.